Plow assemblies having a plurality of plow units mounted to a common or main frame which is pulled behind a tractor or other suitable agricultural implement are well known in the art. As is known, each plow unit is mounted at pre-selected intervals along the main frame which is inclined relative to the direction of travel of the tractor. As the plow assembly is pulled across the field, a trailing plow unit will turn plowed earth into a furrow formed by a preceding plow unit.
At a quick glance, all plow assemblies generally appear alike and serve equal functions. A typical plow assembly arranges the plow units behind and such that they are pulled across a field by the tractor. A typical plow assembly further includes a steering system including a ground engaging steering wheel conventionally arranged at a rear end of the plow assembly. During a plowing operation, the steering system maintains the steering wheel generally parallel to the tractor wheels. In response to turning of the tractor, the steering system angles the steering wheel thereby facilitating turning of the plow assembly with the tractor.
Notwithstanding the similarities, the agricultural industry has distinctively characterized plow assemblies into two types: "In-Furrow" and "On-Land" plow assemblies. An "In-Furrow" plow assembly is typically used with a small type tractor and has three to six plow units arranged in combination therewith. A rear wheel of the tractor is arranged to ride in a previously plowed furrow and, thus, the name "In-Furrow" plow assembly. During use, an "In-Furrow" plow assembly is generally restricted to turn approximately 30.degree. to 35.degree. to each side of the direction of travel of the tractor. If an "In-Furrow" plow assembly is forced to turn more than 30.degree. to 35.degree. to either side of the direction of travel of the tractor, the plow assembly will most likely be damaged. Such damage will result from a rear tractor wheel impacting with a portion of the plow assembly or the plow assembly falling over upon itself, thus, lending itself to damage. Such damage will not only necessitate downtime to repair, but also requires a replacement plow assembly to continue the plowing operation.
A "On-Land" plow assembly typically includes six or more plow units. The additional plow units require a larger size tractor to develop the necessary pulling power for such plow assemblies. As compared to an "In-Furrow" plow assembly, an "On-Land" plow assembly allows the tractor wheels to ride on-land adjacent a previously plowed furrow. The larger tractors sometimes use articulated steering and, thus, provide a shorter turn radius. The shorter turn radius of such larger tractors, requires the "On-Land" plow assemblies to be designed to turn approximately 60.degree. to 75.degree. to each side of the direction of the tractor.
From inventory and manufacturing cost perspectives, it is beneficial to duplicate as many parts as possible between the two different plow assemblies. The design and turning limitations (35.degree.) of an "In-Furrow" plow assembly in each direction of tractor travel does not, however, lend itself to the tighter turning radius of larger tractors. An "In-Furrow" plow assembly may allow the steering wheel of the steering system to slide across the field when the turning limitation (35.degree.) of the tractor is exceeded. The larger turning angle (60.degree. to 75.degree.) of a larger tractor, however, greatly exceeds the turning limitations of an "In-Furrow" plow assembly and would likely result in damage to an "In-Furrow" plow assembly if the two were used in combination with each other. As will be appreciated, an "In-Furrow" steering system will not properly function with an "On-Land" plow assembly because of the relatively large steering angle of the tractor during a turning motion. Thus, and although they appear similar, the "In-Furrow" and "On-Land" plow assemblies require separate and distinct parts which substantially increase inventory and manufacturing costs for the different plow assemblies.
Most conventional plow assemblies have the capability of changing spacing between adjacent plow units. Heretofore, adjusting the spacing between adjacent plow units has been a tenuous and time-consuming task. Thus, it would be advantageous to permit the spacing between adjacent plow units to be changed without requiring extensive operator involvement.
Thus, there is a need and desire for a plow assembly capable of successfully permitting a relatively large turning angle of a tractor relative thereto and wherein the plow units can be easily adjusted to vary the spacing therebetween preferably through a continuous range of spacings.